How to control behavior for ChannelClosedMessage

We use the session-manager-plugin in a DevOps tool of ours and we would like to have more control over the shutdown / program ending logic. Currently this is not possible, because session-manager-plugin calls `os.Exit(0)` after a `ChanellClosedMessage` is received. IMHO, this is pretty rude behavior for a library package, because it event prevents the usage of `defer`-ed function for more graceful shutdown.

Therefore I wonder, what is the reason for this and what options do exist to take more control over the program shutdown if session-manager-plugin is used.